/*
 * Copyright (c) 2020 - present, Inspur Genersoft Co., Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.inspur.edp.cef.entity.event;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.Objects;
import java.util.function.Consumer;

public class EventHandlerList {

  private HashMap<Object, LinkedList<Object>> listeners;

  public void addListener(Object key, Object listener) {
    Objects.requireNonNull(key);
    Objects.requireNonNull(listener);

    findOrCreate(key).add(listener);
  }

  public void removeListener(Object key, Object listener) {
    Objects.requireNonNull(key);
    Objects.requireNonNull(listener);

    findOrCreate(key).remove(listener);
  }

  public <T> void Fire(Object key, Consumer<? super T> consumer) {
    Objects.requireNonNull(key);
    Objects.requireNonNull(consumer);

    for (Object listener : findOrCreate(key)) {
      consumer.accept((T) listener);
    }
  }

  private LinkedList<Object> findOrCreate(Object key) {
    if(listeners == null){
      listeners = new HashMap<>();
    }
    LinkedList<Object> rez = listeners.get(key);
    if (rez == null) {
      rez = new LinkedList<Object>();
      listeners.put(key, rez);
    }
    return rez;
  }
}
